Process for eliminating gases from viscose silk cakes or cheeses



Oct. 10, 1933. J. KOOYSTRA 1,930,392

. PROCESS FOR ELIMINATING GASES FROM VISCOSE SILK CAKES 0R CHEESES Filed Sept. 28, 1929 WW/ &4

Patented Oct. 10, 1933 UNITED STATES PROCESS FOR ELIMINATING GASES FROM VISCOSE SILK CAKES OR CHEESES Jan Kooystra, Arnhem, Netherlands, assignor, by

mesne assignments, to American Enka Corporation, Wilmington, Del., a corporation of Delaware Application September 28, 1929, Serial 395,959, and in the Netherlands September 28,

3 Claims.

My invention relates to a process for eliminating gases from viscose silk cakes or cheeses.

Although the technical measures now adopted in up-to-date artificial silk works are such that i the operatives in the spinning mills are not exposed to injury from the dangerous gases, it is also desirable to eliminate, as far as possible, the gases present in the freshly spun material, in order that the operatives engaged in subsequent 14 processes may also be protected from injury or inconvenience.

In the production of artificial silk from unripe viscose, it is known to treat the spun material with alkali hydroxides, in order to eliminate car- -bon disulphide. It is also known to treat the material with warm water, for the purpose of recovering carbon disulphide. Moreover, it has already been suggested to treat the fresh artificial silk, in bobbin form, with steam and ammonia, and centrifuge or evacuate, in order to remove the gaseous products, such as sulphuretted hydrogen and carbon disulphide. Although these treatments may be applied with more or less success, they are nevertheless generally attended with the drawbacks of taking a comparatively long time and of insufficiently destroying the carbon disulphide in the spun material. I The process for eliminating gases from viscose silk cheeses according to my present invention, is characterized in that air or other harmless gas at a temperature of at least 50 C. is passed for a short period through the spun cakes or cheeses.

A feature of my process is that it may be carried out by superimposing the cakes or cheeses, with interposed plates, each of which has a central opening, with uppermost cakes or cheeses being covered over and the gaseous medium is then aspirated through the cakes or cheeses.

Another feature of my invention is that the process may be carried out by closing the spining bowl, with the spun cake or cheese, by a tight-fitting cover, and forcing in, or aspirating,

the gaseous medium by means of a member disposed in the interior of the bowl.

My invention will now be explained with reference to the accompanying drawing, in which two typical embodiments of apparatus for carrying out the process are illustrated.

Fig. 1 is a sectional elevation of a frame on which are mounted two rows of spinning cakes or cheeses.

Fig. 2 is a vertical section through a spinning bowl with a pressure device for the warm gaseous medium to be introduced.

As can be seen from the drawing, the arrangement according to Fig. 1 consists of a frame 1, in which the spun cakes or cheeses 2 are stacked one upon another, with interposed plates 3 provided with a central opening 4. In the example represented, five cakes or cheeses are superimposed, the top one being covered by a plate 5. At approximately midway of the axis of symmetry of the cakes or cheeses are disposed evacuation pipes 6 opening into a common pipe 7. This frame is set up in a closed box having an atmosphere of warm air, preferably containing steam. The warm air penetrates through the sides of the cakes or cheeses and is drawn off through the central openings 4 by pipes 6, 7.

In Fig. 2, the spinning bowl 8 is provided with openings 9 through which, in the spinning process, the spinning-bath liquid adhering to the filaments is centrifuged. The bowl is closed by an ordinary cover 10, which is pressed on to the seating 12 of the bowl, for example by a rubber ring 11. Inserted in the central opening of the cover 10 is a tubular member 13 which fits tightly into the tapering rim of the opening in the cover 10. Said member 13 is provided with apertures 14 of progressively increasing diameter downwards, and is fitted with a connection 15, attached to the pipe through which air at about C. is forced into the apparatus. Owing to the progressively increasing diameter of the apertures 14 in the downward direction, said air is distributed uniformly in the interior of the bowl, without setting up eddies. The warm air penetrates through the cakes or cheeses 16, and leaves the bowl by way of the openings 9.

I have found in practice that, by operating at a temperature of (SO- 0., the carbon disulphide, amounting usually to 2-3%, in the cakes or cheeses can be eliminated, in a practically complete manner, within a few minutes. After aspirating for about a minute, the content of carbon disulphide is even reduced to 0.1%, without the quality of the cakes or cheeses being impaired in any way. Similar results are obtained by using the device according to Fig. 2.

I claim:

1. Process for eliminating gases from viscose silk cakes or cheeses characterised in that air or other harmless gas at a temperature of at least 50 C. up to 80 C. is passed for a short period of about ten minutes through the walls HIS one upon the other suitably separated in order to form a continuous chamber within their walls, forcing air or harmless gas at a temperature ranging from 50 C. to C. for about ten minutes through the walls of the cakes into said chamber and finally withdrawing said air or harmless gas mixed with said injurious gases in axial direction from said chamber.

JAN KOOYSTRA. 

